Dust collector for grinding tool

ABSTRACT

The disclosure is directed to an improved dust collector for a manually operable grinder comprising a hood overlying the top of a cupstone grinding wheel and having a depending skirt to form a dust-collecting chamber and at least one passage through the back wall of the cupstone wheel for connecting its hollow center to the dust-collecting chamber. With the added passages in the back wall of the cupstone wheel the edge of the depending skirt of the hood may be located at a height so as not to interfere with the use of the lower peripheral edge of the wheel.

United States Patent Assignee Inventor Guy F. Cusumano Englishtown. NJ.795,901

Feb. 3, i969 July-27, 1971 Clarkson Industries. Inc. New York, NY.

Appl. No. Filed Patented DUST COLLECTOR FOR-GRINDING TOOL PrimaryExaminer-James L. Jones, Jr. Attorney-Curtis. Morris & Safford ABSTRACT:The disclosure is directed to an improved dust collector for a manuallyoperable grinder comprising a hood overlying the top of a cupstonegrinding wheel and having a depending skirt to form a dust-collectingchamber and at least one passage through the back wall of the cupstonewheel for connecting its hollow center to the dust-collecting chamber.With the added passages in the back wall of the cupstone wheel the edgeof the depending skirt of the hood may be located at a height so as notto interfere with the use of the lower peripheral edge ofthe wheel.

DUST COLLECTOR FOR GRINDING TOOL The present invention relates to handgrinding tools and more particularly to an improved dust collector for amanually operated grinder.

Manually operating grinding tools have been in common use for a longperiod of time to snag rough castings by grinding off the flashings andsprues remaining on the casting after removal from the mold. The mostcommon type of grinder for this purpose comprises a cupstone grindingwheel rotatably mounted on a frame and driven by a suitable motor. Thecupstone grinding wheel has continuous back and sidewalls to form aninverted cup, usually of frustoconical shape, but sometimes in the formofa right cylinder. The outer rim of the continuous sidewall has a flatannular grinding surface which surrounds an opening at the center.Radially extending handles project from the frame to manually guide theimplement when its flat annular grinding surface engages the surface ofthe part being ground. Also, the angular edge between the sidewall andannular grinding surface of the cupstone is used by the operator toundercut projections on the part or casting being ground, and the toolis many times held at an angle to the surface to obtain a grindingeffect only at the outer peripheral edge ofthe wheel.

Operation of the grinding implement produces dust which constitutes ahealth hazard. It has heretofore been proposed to provide adust-collecting shield or hood around the periphery of the wheel inwhich a partial vacuum is maintained to draw off the dust in the streamof air flowing into the hood. Such hoods have a skirt which extendsdownwardly to a position closely adjacent the work to increase thevelocity of the air flowing into the hood and thereby insure thecollection of all dust generated by the wheel. However, the location ofthe lower edge of the skirt of such dust-collecting hoods interfereswith the use of the angular edge of the cupstone wheel and the tiltingof the implement as practiced by many operators. To overcome thisdifficulty it also has been proposed to use a dust-collecting hood orshield that extends to a position adjacent the annular grinding surfacearound the greater part of its circumference, but eliminating the hoodfrom a small sector of the wheel to adapt the edge at that portion to beused without interference from the hood. Grinding tools with suchdust-collecting hoods have been found awkward to use and have not beenfavorably accepted by the trade.

One of the objects of the present invention is to provide an improveddust-collecting arrangement for a grinding wheel of the type indicatedwhich is more efficient in operation in removing dust produced by thegrinding operation and one which facilitates manipulation by theoperator.

Another object is to provide an improved dust collector for a cupstonegrinding wheel which does not interfere with the use ofthe peripheraledge ofthe wheel.

Still another object is to provide an improved dust collector foracupstone grinding wheel which is of simple and compact construction,economical to manufacture and one which is reliable in operation.

These and other objects will become more apparent from the followingdescription and drawing in which like reference characters denote likeparts throughout the several views. It is to be expressly understood,however, that the drawing is for the purpose of illustration only and isnot a definition of the elements of the invention, reference being hadfor this purpose to the appended claims.

In the drawing:

FIG. 1 is a side elevational view ofa conventional cupstone grindingtool incorporating the novel dust-collecting arrange ment of the presentinvention and showing the implement tilted to adapt the peripheral edgeof the wheel to be used in a conventional way;

FIG. 2 is an enlarged side elevational view of the implement partly insection to show the dust-collecting hood and openings in the backwall ofthe cupstone wheel for directing streams ofair into the dust-collectingchamber;

FIG. 3 is a bottom plan view of the grinding implement illustrated inFIGS. I and 2 to show the arrangement of the holes in the backwall ofthe cupstone wheel for directing dust into the collection chamber; and

FIG. 4 is a side elevational view partly in section of a grindingimplement having a cupstone grinding wheel of right cylindrical form.

Referring now to the drawing, the novel features of the presentinvention are shown applied to a manually operated grinding toolcomprising a frame in which a depending shaft 11 is rotatably mountedand which, in turn, mounts a cupstone grinding wheel 12 at its lowerend. The frame 10 encloses a driving motor I3 which may be of anysuitable type. In the illustrated embodiment, the motor 13 isillustrated as an air-driven turbine wheel connected to the upper end ofshaft 11 and supplied with air under pressure through an air connectionl4 and a nozzle 15 constituting one of the handles for holding theimplement. However, it will be understood that the motor 13 may beelectrically or hydraulically operated. A similar handle 16 projectsradially from the casing 10 to adapt the implement to be held by theoperator in his two hands.

The cupstone grinding wheel 12 shown in FIGS. 1 to 3 has a frustoconicalshape and comprises a continuous backwall l7 and peripheral sidewall 18and forming a hollowcenter 19. The backwall 17 has a reinforcing plate20 formed as an integral part of the wall and a central insert 21 havinga tapped bushing 22 for receiving the lower threaded end 23 of the shaft11. Shaft 11 has a stepped shoulder 24 against which the reinforcingplate 20 engages to limit the relative movement of the cupstone wheelalong the shaft 11. The outer end of the sidewall 18 provides a flatannular grinding surface 25 and the junction of this surface with theconical sidewall forms an annular peripheral cutting edge 26. As thusfar described, the

grinding implement is identical with those in common use.

In accordance with the present invention, an improved dustcollectingarrangement is provided which insures the removal of ground dust toeliminate any health hazard but does not interfere with the operation ofthe implement. As shown most clearly in FIG. 2, the dust collectorcomprises a hood having a flat backwall 31 which abuts and is attachedto the bottom of the frame 10 by means ofscrews 32. The hood 30 has adepending skirt 33 of the same general frustoconical shape as the shapeof the cupstone wheel 12, but of slightly greater diameter, so that thelower edge portion 33a of the skirt 33 overlies the upper peripheraledge of the reinforcing plate 20 of the wheel 12 only, to provide anannular space 34 therebetween. The hood 30 and plate 20 of the cupstonewheel 12 form a dust-collecting chamber 35 therebetween which ispartially evacuated through a flexible suction line 36 to produce a flowof air through the annular space 34. In addition, the backwall 17 of thecupstone wheel 12 has a series of holes 40 extending therethrough andthrough the reinforcing plate 20 to provide additional passages throughwhich airladen dust may flow into the dust-collecting chamber 35. Byproviding the additional passages 40 through the backwall 17 of wheel 12for dust-laden air, the lower edge portion 33a of the skirt 33 of thehood 30 may be located a sufficient distance above the edge 26 of thecupstone wheel 12 to permit the edge to be used to undercut projectionsor grind a flat surface 41 on the casting 42, or to adapt the conicalside 43 of the wheel to engage an edge 44 of the casting and to adaptthe implement as a whole to be tilted to the position shown in FIG. 1.

In operation the grinding implement is used in the usual way by placingthe flat annular surface 25 against a flat surface 41 of a part to beground, or by tilting the implement in the manner illustrated in FIG. Ito use the laterally projecting edge 26 or inclined side 43 of the wheelfor grinding. Any dust produced by such grinding is drawn into theannular curtain of air flowing up the side of the wheel into the annularpassage 34, or is caught in a stream of air flowing along the bottomsurface 25 and into the open center 19 of the cupstone l2 and thenthrough the passages 40 into the dust-collecting chamber 35. In bothcases the dust is withdrawn through the suction line 36 to a collectionunit where the dust is separated from the air. It has been found inpractice that the central passages 40 in the backwall 17 of the grindingwheel 12 so supplement the removal of dust through the annular passage34 adjacent the top of the wheel as to produce as good or even betterdust removal than the prior constructions having hoods extending to aposition adjacent the bottom of the wheel.

FIG. 4 illustrates a modified construction of cupstone wheel 12a in thefonn ofa right cylinder. The wheel 12a in FIG. 4 has a continuousbackwall 17a and sidewall 18a to form the open center 19 1. The backwall17a is also provided with the spaced passages 40a the same as in thefrustoconical wheel illustrated in FIGS. 1 and 2. However, the outerperiphery of the sidewall 18a constitutes a cylindrical surface, insteadof a frustoconical surface, but the skirt 33a depending from the hood30a need only extend down a short distance below the top of the backwall17a to insure adequate dust removal, due to the additional passages 40ain the backwall ofthe wheel.

It will now be observed that the present invention provides an improveddust-collecting arrangement for a manually operated cupstone grindingimplement which is more facile and efficient in operation. It will alsobe observed that the present invention provides an improveddust-collecting arrangement for a cupstone wheel which does notinterfere with the use of the edge of the tool during operation. It willstill further be observed that the present invention provides animproved dust collector for a cupstone grinding wheel which is ofextremely simple and compact construction, adapted for economicalmanufacture, and one which is reliable in operation.

While two embodiments of the invention are herein illustrated anddescribed, it will be understood that further modifications may be madein the construction and arrangement of elements without departure fromthe spirit or scope of the invention. For example, the top of thereinforcing plate of the rotating cupstone may have vanes formed thereonto augment the vacuum-producing means and increase the velocity of airflow to .the dust-collecting chamber. Therefore, without limitation inthis respect, the invention is defined by the following claims:

I claim:

1. A grinding tool having a cup-shaped grinding stone with a continuousback and sidewalls to form a hollow center, a motor connected to rotatethe cupstone wheel, a hood overlying the backwall of the cupstone wheelin spaced relation thereto to form a chamber therebetween, said hoodhaving a depending skirt overlying the outer periphery of the backwallof the cupstone wheel in spaced relation thereto to form an annularpassage therebetween, the backwall of the cupstone wheel having aplurality of unobstructed openings therein between its hollow center andthe chamber, and means for producing a partial vacuum in the chamber tocause dust produced by the cupstone wheel to flow into thedust-collecting chamber through the annular passage around the peripheryof the cupstone and the openings from the hollow centerv 2. A grindingtool in accordance with claim 1 comprising a frame, a motor mounted onthe frame and having a shaft with a threaded end, the cupstone wheelhaving a tapped fitting, the hood being supported on the frame in spacedrelation to the backwall of the cupstone and having a depending skirtoverlying the upper periphery of the cupstone in spaced relationthereto, and the means for producing a partial vacuum comprising asuction line and a source of partial vacuum.

3. A grinding tool in accordance with claim 1 in which the cupstone hasan outer periphery in the form of a truncated cone, and the skirt of thehood depending to overly the top of the sidewall of the cupstone for ashort distance only so that the angular corner at the bottom of thecupstone projects outwardly beyond the skirt whereby to prevent thedepending skirt from interfering with the use of the corner edge of thestone.

4. A grinding tool in accordance with claim I in which the cu stone hasan outer Iperiphery in the form of a right ey inder, the depending s irtof the hood overlapping the top of the sidewall of the cupstone for ashort distance only so that the angular corner at the bottom of thecupstone can be tilted to engage the surface of a workpiece withoutinterference by the depending skirt of the hood.

5. A grinding tool comprising, in combination, a frustoconical grindingwheel having relatively small diameter and a relatively large diameterend surfaces, a motor connected to rotate said wheel, a hood positionedadjacent to said small diameter surface to form a chamber therebetween,said hood having a depending skirt extending a short distance only alongthe conical surface of said wheel and spaced therefrom to form anannular passage, and means for producing a partial vacuum in saidchamber to cause dust produced by the grinding action of said wheel toflow through said annular passage into said chamber.

6. A grinding tool according to claim 5 wherein the diameter of saidlarge diameter surface is greater than the diameter of the lowerperiphery of said skirt to prevent said hood from interfering with usageof the peripheral portions of said wheel near said large diametersurface.

7. A grinding tool comprising, in combination, a frustoconi cal cupstonegrinding wheel having a continuous back and sidewalls cooperating todefine a central cavity therein, a motor connected to rotate said wheel,a hood positioned adjacent to said backwall to form a chambertherebetween, said hood having a depending skirt that extends a shortdistance only along the conical surface of said grinding wheel, aplurality of passages extending through said backwall from said cavityto said chamber and means for producing a partial vacuum in said chamberto cause dust produced by the grinding action of said wheel to flowthrough said passages into said chamber.

8. A grinding wheel according to claim 7 wherein the maximum diameter ofsaid wheel is greater than the maximum diameter of-said skirt to preventsaid hood from interfering with usage of the larger diameter portions ofthe conical surface of said wheel.

1. A grinding tool having a cup-shaped grinding Stone with a continuousback and sidewalls to form a hollow center, a motor connected to rotatethe cupstone wheel, a hood overlying the backwall of the cupstone wheelin spaced relation thereto to form a chamber therebetween, said hoodhaving a depending skirt overlying the outer periphery of the backwallof the cupstone wheel in spaced relation thereto to form an annularpassage therebetween, the backwall of the cupstone wheel having aplurality of unobstructed openings therein between its hollow center andthe chamber, and means for producing a partial vacuum in the chamber tocause dust produced by the cupstone wheel to flow into thedust-collecting chamber through the annular passage around the peripheryof the cupstone and the openings from the hollow center.
 2. A grindingtool in accordance with claim 1 comprising a frame, a motor mounted onthe frame and having a shaft with a threaded end, the cupstone wheelhaving a tapped fitting, the hood being supported on the frame in spacedrelation to the backwall of the cupstone and having a depending skirtoverlying the upper periphery of the cupstone in spaced relationthereto, and the means for producing a partial vacuum comprising asuction line and a source of partial vacuum.
 3. A grinding tool inaccordance with claim 1 in which the cupstone has an outer periphery inthe form of a truncated cone, and the skirt of the hood depending tooverly the top of the sidewall of the cupstone for a short distance onlyso that the angular corner at the bottom of the cupstone projectsoutwardly beyond the skirt whereby to prevent the depending skirt frominterfering with the use of the corner edge of the stone.
 4. A grindingtool in accordance with claim 1 in which the cupstone has an outerperiphery in the form of a right cylinder, the depending skirt of thehood overlapping the top of the sidewall of the cupstone for a shortdistance only so that the angular corner at the bottom of the cupstonecan be tilted to engage the surface of a workpiece without interferenceby the depending skirt of the hood.
 5. A grinding tool comprising, incombination, a frustoconical grinding wheel having relatively smalldiameter and a relatively large diameter end surfaces, a motor connectedto rotate said wheel, a hood positioned adjacent to said small diametersurface to form a chamber therebetween, said hood having a dependingskirt extending a short distance only along the conical surface of saidwheel and spaced therefrom to form an annular passage, and means forproducing a partial vacuum in said chamber to cause dust produced by thegrinding action of said wheel to flow through said annular passage intosaid chamber.
 6. A grinding tool according to claim 5 wherein thediameter of said large diameter surface is greater than the diameter ofthe lower periphery of said skirt to prevent said hood from interferingwith usage of the peripheral portions of said wheel near said largediameter surface.
 7. A grinding tool comprising, in combination, afrustoconical cupstone grinding wheel having a continuous back andsidewalls cooperating to define a central cavity therein, a motorconnected to rotate said wheel, a hood positioned adjacent to saidbackwall to form a chamber therebetween, said hood having a dependingskirt that extends a short distance only along the conical surface ofsaid grinding wheel, a plurality of passages extending through saidbackwall from said cavity to said chamber and means for producing apartial vacuum in said chamber to cause dust produced by the grindingaction of said wheel to flow through said passages into said chamber. 8.A grinding wheel according to claim 7 wherein the maximum diameter ofsaid wheel is greater than the maximum diameter of said skirt to preventsaid hood from interfering with usage of the larger diameter portions ofthe conical surface of said wheel.